The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A conventional automatic transmission includes a hydraulic system operable to circulate a hydraulic fluid, such as an oil, throughout the transmission. The hydraulic fluid provides multiple functions to the components of the transmission including, but not limited to, lubrication of the clutches and gearsets, cooling of components that generate excessive heat, and hydraulic control of valves, solenoids, and clutch pistons. However, typical hydraulic fluids employed in transmissions are susceptible to being entrained with air (i.e., aerated). Air does not lubricate nor provide cooling as effectively as the hydraulic fluid. Accordingly, although the requisite volume of oil is seemingly being pumped to provide sufficient cooling and lubrication to the transmission, the lubrication and cooling is insufficient. As a consequence, the components of the transmission may overheat and bearings and other moving parts may prematurely fail. Additionally, it can lead to pump cavitations and excessive softness in hydraulically actuated components. The hydraulic fluid in the transmission may become aerated in various parts of the system since the system is not sealed from the environment. Additionally, the sump that stores the hydraulic fluid typically contains air.
One solution to account for aeration is to increase the amount of hydraulic fluid communicated throughout the system. However, this solution increases the cost and weight of the system. Accordingly, there is a need in the art for a system that de-aerates hydraulic fluid as it is communicated throughout the transmission in order to reduce the volume of hydraulic fluid needed, increase lubrication and cooling, eliminate pump cavitation and soft hydraulic control actuation without substantially increasing cost and weight.